Aircraft launching and arresting device



July 28, 1964 J. J. BYRNE ETAL AIRCRAFT LAUNCHING AND ARRESTING DEVICEFiled July 12, 1961 12 Sheets-Sheet l INVENTORS JOHN J. BYRNE 6 ROBERT WCRUGER O EYS July 28, 1964 J. J. BYRNE ETAL 3,142,453

AIRCRAFT uumcamc AND ARRESTING DEVICE Filed July 12. 1961 12Sheets-Sheet 2 AIR OIL INVENTORS JOHN J. BYRNE 8 BY ROBERT W. ORUGERwamwwTmfi/mwb TTORNEYS July 28, 1964 J. J. BYRNE ETAL AIRCRAFT LAUNCHINGAND ARRESTING DEVICE 12 Sheets-Sheet 5 Filed July 12, 1961 INVENTORSJOHN J. BYRNE 8: ROBERT W. CRUGER v BY 342;) ATT NEYS July 28, 1964 J.J. BYRNE ETAL 3,142,458

I AIRCRAFT LAUNCHING AND ARRESTING DEVICE Filed July 12, 1961 12Sheets-Sheet 4 FIG. 4

0) nvmvrons 3 JOHN J. BYRNE a By ROBERT w. CRUGER TTORNEYS July 28, 1964J. J. BYRNE ETAL 3,142,458

AIRCRAFT LAUNCHING AND ARRESTING DEVICE Filed July 12. 1961 12Sheets-Sheet 5 .1 4%??? JOH 6 Y ROBERT W. CRUGER TTORNEYS July 28, 1964J. J. BYRNE ETAL 3,142,458

AIRCRAFT LAUNCHING AND ARRESTING DEVICE Filed July 12, 1961 12Sheets-Sheet 6 INVENTORS JOHN J. BYRNE a RQBERT w. CRUGER A TORNEYS July28, 1964 .1. J. BYRNE ETAL AIRCRAFT LAUNCHING AND ARRESTING DEVICE l2Sheets-Sheet 7 Filed July 12, 1961 ZOELwOL Ill/ll IN V EN TORS #LSJLLJ.A TORNEYS July 28, 1964 J. J. BYRNE ETAL 3,142,458

AIRCRAFT LAUNCHING AND ARRESTING DEVICE Filed July 12, 1961 12Sheets-Sheet 8 FIG. 9 26L.

: POSITION 2 \is POSITION I JOHN J wa F|G IO BYROBERT Wcnusea AT RNEYSJuly 28, 1964 J. J. BYRNE ETAL 3,142,453

AIRCRAFT LAUNCHING AND ARRESTING DEVICE Filed July 12, 1961 1,2Sheets-Sheet 9 INVENTORS JOHN J. BYRNE 8| BY ROBERT W. CRUGER July 28,1964 J. J. BYRNE ETAL AIRCRAFT LAUNCHING AND ARRESTING DEVICE Filed July12, 1961 12 Sheets-Sheet 1O FIG. l3

INVENTORS JOHN J. BYRNE a BY ROBERT w. CRUGER TTORNEYS bdk h July 28,1964 J. J. BYRNE ETAL 3,142,458

AIRCRAFT LAUNCHING AND ARRESTING DEVICE Filed July 12, 1961 l2Sheets-Sheet l1 INVENTORS JOHN J. BYRNE 8 ROBERT W. GRUGER ATTORNEYSJuly 28, 1964 J. J. BYRNE ETAL AIRCRAFT LAUNCHING AND ARRESTING DEVICEl2 Sheets-Sheet 12 Filed July 12. 1961 FIG. I?

INVENTORS JOHN J. BYRNE a nfissa'r w. CRUGER baQd-Ja ATTORN EYS UnitedStates Patent 3,142,458 AIRCRAFT LAUNCHING AND ARRESTING DEVICE John J.Byrne and Robert W. Cruger, both of Philadelphia, Pa., assignors to E.W. Bliss Company, Canton, Ohio, a corporation of Delaware Filed July 12,196i, Ser. No. 123,527 31 Claims. (Cl. 24463) This invention relates ingeneral to aircraft launching and arresting means, and more particularlyto mechanical and hydraulic rotary energyabsorbing engines employed inassociation with aircraft launching and arresting means. Thisapplication is a continuation-in-part of our co-pending parentapplication, Serial No. 778,723, filed December 8, 1958, now abandoned.Patent application Serial No. 778,723 was co-pending with our patentapplication Serial No. 773,220, filed November 12, 1958, now Patent No.2,977,076, issued March 28, 1961. All of the disclosure of application,Serial No. 773,220 was specifically incorporated by reference intoapplication, Serial No. 778,723, and said disclosure is likewiseincorporated by reference into this present continuation-in-partapplication.

The general scheme for arresting the forward speed of aircraft making alanding on an airstrip, the deck of an aircraft carrier, or the like, isto provide a pendant which is placed transversely across the path of theaircraft to be intercepted by an aircraft hook, or a portion of theaircraft itself. The opposite ends of the pendant are secured to payoutmeans which will permit the pendant to yield with the aircraft and yetat the same time provide predetermined resistance to the aircraftsforward motion of a magnitude sufiicient to bring the aircraft to a stopwithin a predetermined distance and in a safe and gradual manner.Although the general increase in aircraft size and landing speeds hasmade our invention necessary, its importance is particularly accentuatedwith the advent of jet aircraft which land at even higher speeds, andrequire even longer runways than heretofore.

In the process of arresting the forward movement of an aircraft, theenergy of motion of the aircraft must be translated into another form,and it is the object of our invention to provide an energy absorbingmeans which operates in a novel and improved manner over presentlyexisting devices for absorbing the energy of landing aircraft. It isanother object of our invention to provide an energy arresting devicewhich is compact, easily transported, installed and operated, and whichis suitable for expeditionary type purposes, as well as commercial use.It is yet another object of our invention to provide an improvedaircraft arresting device which provides resistance to aircraft movementproportional to the speed of the aircraft. It is still another object ofour invention to provide a means to modulate the peak to mean load onthe system whereby maximum energy is absorbed when short runwayarrestment is necessary. A further object of our invention is theprovision of a low inertia, high engaging speed, high energy absorber. Astill further object of our invention is the provision of energyabsorbing engines arranged in a novel tandem relationship for increasedenergy absorbing capacity. Yet a still further object of our inventionis the provision of an energy absorbing system adapted to respond tooff-center loading, and pendant en gagement permitting a differentialpayout at opposite pendant ends.

Inasmuch as launching and arresting operations as they relate to ourinvention are substantially the reverse of each other, it is yet anotherobject of our invention to provide a single mechanism which serves thedual purpose of both launching and arresting aircraft. Still another andimportant object of our invention resides in the provision of novelpayout reel and tape means equally adapt- 3,142,458 Patented July 28,1964 able with the several embodiments of the invention contemplated,disclosed and discussed in this specification. Another object of ourinvention resides in the provision of novel reel and tape means equallyadvantageous in both arresting and launching functions of embodiments ofthe invention. Another object of our invention resides in theutilization of a tape of novel configuration adapted to permit superiorcoaction with its reel means in both launching and arresting operations.It is still another object of this invention to provide an aircraftarresting engine having programming means adapted to regulate andcontrol force versus runout relationships. It is .still yet anotherobject of this invention to provide an aircraft launching and arrestingsystem which can quickly be re-set for substantially continuousoperation.

Other objects of our invention willl become apparent from a reading ofthe specification, taken in consideration with the drawings and appendedclaims.

FIGURE 1 is a pictorial perspective view of the general organization ofour invention shown in association with an aircraft in the process ofbeing launched;

FIGURE 2 is a schematic perspective view of a preferred embodiment of alaunching and arresting system employed in the invention; 4

FIGURE 3 is a side elevational view of the launching and aresting engineshown in schematic perspective in FIGURE 2;

FIGURE 4 is a front elevational view of the launching and arrestingengine shown in FIGURE 3;

FIGURE 5 is a schematic plan view of the launching and arresting systemshown in FIGURE 2;

FIGURE 6 is a perspective view of a tandem arrangement of a launchingand arresting engine embodiment employed for heavy duty arrestingoperations;

FIGURE 7 is a schematic perspective view of another embodiment of alaunching and arresting system employed in the invention;

FIGURE 8 is a side elevational view with parts in section of thelaunching and arresting engine taken onthe line 88 of FIGURE 9;

FIGURE 9 is a sectional elevational View of the launching and arrestingengine taken on the line 9--9 of FIG- URE 8;

FIGURE 10 is a plan view of a runway showing an aircraft in two stagesof arrestment corresponding to the two stages of reel payout shown inFIGURE 8;

FIGURE 11 is a plan view of a modified embodiment of the launching andarresting system shown in FIG-i, URE 5;

FIGURE 12 is an elevational view with parts in section showing the useof a water brake in another preferred embodiment of the invention; and JM FIGURE 13 is a schematic view of a hydraulic feed and control systemused in conjunction with the water brake shown in FIGURE 12.

FIGURE 14 is a plan view of a synthetic fiber tape employed in apreferred embodiment of the invention;

FIGURE 15 is a sectional view taken on the line 15-15" of FIGURE 14;

FIGURE 16 is a fragmentary side elevationalview taken on the line 16-16of FIGURE 14;

tern of transverse strands employed in the tape of FIG- URES 14 through17; V

FIGURE 19 is an elevational view of the means to weave the tape ofFIGURE 14; and

FIGURE 20 is a plan view of the apparatus shown in FIGURE 19.

Although the preferred embodiments of our invention"- may be used inboth launching and arresting operations,-

indeed this being one of the features of utility of the invention, stillthe operation of the inventive equipment is somewhat different inlaunching as compared to arresting. Accordingly, both the aircraftarresting and launching features of preferred embodiments of theinvention will be discussed in detail to provide complete understandingof our inventive concept.

Referring now to the drawings in greater detail, and particularly toFIGURE 1, a typical installation is shown wherein our invention isemployed to launch and arrest aircraft on runways normally too short toaccommodate planes of a given type, weight, and speed. A runway R isprovided with a runway flush center track B for guiding a launchingchock C securable to an appropriate appendage D of the aircraft A.Positioned to one side of the runway is to be found one embodiment ofour combination takeup, payoff and energy absorber reel 1, which inlaunching operations is driven by a jet turbine 2 connected to thecombination takeup reel and energy absorber by means of shafting 3 andclutch 4. The installation is controlled by an operator positioned infront of a control panel 5 conveniently placed in a position of vantagefor viewing the runway. The jet turbine 2 may be of considerably lesscapacity for arresting operations than for combination arresting andlaunching operations, all as will be developed hereinafter.

A fiat nylon tape such as shown and described in our Patent No.2,977,076, is secured to the combination takeup and payoff reel 1, itbeing also understood that when reference is made to this reel, it iseither a takeup reel or a payoff reel without modification, depending onits function at the moment, whether it be launching, arresting, orrewinding. Accordingly, this reel will henceforth be referred to withoutany further designation as to its capacity. 1

The reel 1 is adapted to wind and unwind a pair of fiat nylon tapes 20Aand 20B. Nylon tape 20A partially encased in protective conduits 6 and7, passes between a pair of sheaves 8A, and then extends down the runwayto a fastening device 9A securing the tape to one end of a wire cablependant 12. The other tape passes beneath the runway at F (in protectiveconduits not shown, but similar to conduits 6 and 7) and emerges betweena pair of sheaves 83 to extend downward of the runway for connection bya fastening device 9B to the other end of steel pendant 12. I

To launch an aircraft with the above described apparatus, the pilot ofthe aircraft A brings its engine up to speed at the same time thatturbine 2 is brought up to speed, whereupon aircraft restraining meansare released and takeup reel 1 is engaged to the turbine by clutch 4.The nylon tapes 20A and 20B are wound on respective reel spools 22A and22B until the tapes are entirely rewound, at which time the pendant issubstantially transverse of the runway between sheaves 8A and 8B, andthe aircraft is airborne.

With the steel pendant 12 transverse of the runway R after launching,the system is then automatically in readiness to arrest an aircraftcoming in for a landing. In the arresting operation, suitable pendantintercepting means, such as a hook, landing assemblage or the like (seeFIGURE 2), secured to the aircraft A, engages the steel cable pendant12. After a finite period of time, explained more fully in our PatentNo. 2,977,076, the impact of the aircraft A on the pendant 12 causes thenylon tapes 20A and 20B to turn reel 1 and thereby pay out the tape at asubstantially constant tension designed to bring the aircraft to asmooth, gentle stop within a predetermined distance.

After the aircraft has been arrested according to plan, the arrestingpendant 12 and nylon tapes have been paid out and are extended from onethousand to several thousand feet down the runway. If it is necessarythereafter to recover this tape and rewind it on the reel preparatory toa subsequent arrestment, the jet turbine is then placed into operationto rewind the tape on the reel exactly in the same fashion in which itwas wound when launching aircraft in the manner previously described.Thus, it will become apparent that in both the launching and arrestingfunctions of the apparatus, the jet turbine winds and rewinds the reelin the same angular direction for the same purpose, to-wit: to coil thenylon tape on the reel. The ease and speed with which tape is recoveredon the reel is an important feature of our invention. We havesuccessfully operated our equipment wherein runouts of over one thousandfeet are routinely rewound in less than five minutes without thenecessity of personnel other than the sole operator, and without anyauxiliary equipment. The only other aircraft arresting system actuallyreduced to practice, of which we are aware, requires a crew of about tenmen, two tractors and about forty-five minutes to set up for a secondarrestment.

There is no energy absorbing problem in launching operations inasmuch asall of the energy of the system is expended in getting an aircraftairborne. However, on the arrestment side of the operation, considerableenergy must be dissipated in bringing an aircraft to a stop, and themeans for accomplishing this will now be described.

Reference is made to the drawings in greater detail, and to FIGURE 2 inparticular. An aircraft A is shown making engagement with a pendant 12stretched transverse of the runway R, said aircraft being in the processof arrestment. The opposite ends 16 and 18 of the pendant 12 are securedto a pendant payout means 20, comprising a pair of tapes 20A and 2013which are spirally wound on separate spool portions 22A and 22B of reel1 in such manner that when the reel revolves in the direction of thearrows, the tapes will pay out in opposite directions from the reel topermit the pendant 12 to move with the aircraft down the runway. Spools22A and 22B are coupled with an over-running clutch 22C to permitdifferential angular velocity between the two spools. This isparticularly important during offcenter arrestments wherein the onespool is permitted as a consequence to rotate faster than the other. Theresult is therefore a self-compensating adjustment to the center of therunway.

It will be observed that suitable pairs of sheaves 8A, 8B, and aresecured strategically adjacent the runway to guide the payout movementof the tapes 20A and 208. As suggested by FIGURES 2 and 3, this entirereel mechanism may be encased in a pit P beneath the runway, or in theembodiment of an expeditionary system, shown in FIGURE 1, the reel maybe staked out on the surface adjacent to one side of the runway.

In yet another embodiment of expeditionary gear, the spool portions 22Aand 228 may be split and located on opposite sides of the runway R, asshown in FIGURE 11, thereby avoiding the necessity of tunneling beneaththe runway in order to locate tape 203 such as in FIGURE 1. In theembodiment of FIGURE 11 each spool component is a complete reel unit initself, having both a windup drive motor 2, and a braking system 23. Forpurposes of understanding the invention, a complete discussion of theembodiment shown in FIGURE 2 will be undertaken, which will also explainthe operation of the embodiment shown in FIGURE 11.

Attention is now directed to the hydraulic system of the reel shownschematically in FIGURE 2. A static airoil reservoir 13 is maintainableunder pressure by means of air pump means 15. Oil is directed throughline 17 to shuttle valve 19. Pressure in branch 17A shifts piston 21 tothe right thereby connecting branch line 17B to brake actuator feederline 21F and brake actuator lines 21L and 21R. In a preferredembodiment, United States Air Force B52 bomber brakes (otherwiseidentified as Bendix brake assembly No. 150556) are used for braking.Thus static brake pressure tank 13 maintains pressure on brakes 23L and23R, which in turn maintains pendant 12 in tension transverse of therunway R, and in readiness for interccption by landing aircraft A.

When the pendant is contacted by the aircraft A and shifted to theposition shown in FIGURE 2 in phantom, the pendant payout means 211A and20B rotate the reel 1, which in turn drives hydraulic pump 26, which ischain driven from reel shaft 27. As pump 26 is operated, hydraulic fluidis drawn from pump fluid reservoir 29 through line 31 on the lowpressure sides of the pump, through pump 26, and then outwardly on thehigh pressure side of the pump through line 33. Line 37 is tapped fromline 33 at junction 35, and is connected to a normally open valve whichcontrols the return of fluid through line 41 to the brake fluid tank 29.The fluid also is carried in line 43 through check valve 45 to the rightside of spool valve 19. As the fluid pressure builds in the systemcorresponding to the increased velocity of the reel, the static pressureside of the valve 19 applied by line 17A is overcome and the spoolpiston 21 is shifted to connect feeder lines 43F and ZIP to lines 21Land 21R, whereupon the pressure from the pump 26 replaces the staticpressure from static brake pressure tank 13.

It will be apparent therefore that the faster the reel rotates, thegreater will be the pressure developed in brakes 23L and 23R acting toresist rotation. Thus, when the plane is at its greatest velocity aftercontacting the pendant 12, the resistance to forward movement is thegreatest. As the plane is gradually decelerated, the reel, of course,will decelerate, pump 26 will decelerate, and the pressure in brakes 23Land 23R normally would also tend to decrease. To provide for bettercontrol over aircraft deceleration, or to provide adjustment foraircraft of different sizes, a programming device, now to be described,may be included in the system to assure a more constant or predeterminedpressure throughout the period of arrestment.

Programming means comprising a gear box 49 chain driven from reel shaft27 to rotate a cam 51 which in turn operates a cam follower 53 toprogram the opening and closing of valve 39, and thereby control thepressure in the hydraulic system. One cycle of rotation of the cam 51 isdesigned to provide continuous adjustment in the pressure system duringthe entire runout capacity of the reel. Thus, valve 39 normally open atthe beginning of the arrestment is gradually closed at a predeterminedrate in order to maintain a given pressure, or a controlled rate ofdecline of pressure in the system.

In order to recover the system for a second arrestment a normally closedmanual shutoff valve 55 is opened to relieve the pressure on theoperating pressure side of the spool Valve 19 and thereby permit thepressure from the static brake pressure tank 13 to again shift thepiston 21 to re-establish static pressure on the reel brakes. It will benoted that line 43 is also provided with a relief valve 57 which coactswith valve 55 to relieve pressure on the operating side of the valve 21.The heat generated in brakes 23L and 23R may be dissipated with suitablewater jackets surrounding the brakes. So encased, the brakes canfunction effectively even though arrestments are made consecutively inrapid order. Our system has been tested successfully wherein arrestmentshave been continuously made as rapid as the tapes 20 and pendant 12could be repositioned. To this end, a rewind motor 61 drives gear box61A which is chain driven to a sprocket 63 secured to the end of reelshaft 27 opposite from that of the pump and cam driven belt connections.For expeditionary purposes a motor generator set, or a gasoline ordiesel engine may be adapted as a source of power for rewinding the reelafter an arrestment has been made. Of course it will be recognized thatthe power requirements of the motor must be considerably greater if thesystem is to be used for both launching and arrestment. For dualapplication a jet turbine 2 such as shown in FIGURE 1 could besubstituted for motor 61.

Reference is now made to FIGURE 7, wherein is shown a preferredembodiment of the invention utilized for arrestments of shorter distancethan contemplated for the embodiment of FIGURE 2. Because of therelatively short runout, it is observed that only a single reel 22 maybe employed. An aircraft 10 is shown in FIGURE 7 making engagement witha pendant 12 stretched across runway 14, and said aircraft is in theprocess of being brought to a stop. The opposite ends 16 and 18 of thependant 12 are secured to a pendant payout means 20, preferably nylontape, as aforesaid. The tape 20 is spirally wound upon a reel 22 so thatwhen the reel revolves in the direction of the arrow 23, the tape willpay out in opposite directions from the reel to permit the pendant 12 tomove with the aircraft down the runway. Suitable sheaves 24 are providedwhere needed to guide the movement of the payout tape 20.

As is shown more clearly in FIGURES 8 and 9, the reel 22 is providedwith a pair of gears 25 positioned on opposite sides of the reel. A pairof hydraulic pumps 26L and 26R are mounted on the reel housing 28 (seeFIG- URE 9) and are drivingly connected to pinion gears 30 in meshedengagement with gears 25. A reel drive motor 32 is also provided and isdrivingly connected to gear 25 by means of pinion gear 34 in meshedengagement with ring gear 24. As in the case of the embodiment of FIG-URE 2, the horsepower rating of the rewind motor 32 will depend onwhether this embodiment of the invention is to be used for the dualfunction of both launching and arresting, or for arrestment alone. Thedrive shaft 36 of the motor 32 is coupled with the shaft 38 of piniongear 34 by means of a sliding coupling 40 which is locked to motor driveshaft 36 by pin means 42. Hydraulic brake means 23L and 23R are providedon opposite sides of reel 22 and journaled on reel shaft 46 with respectto the portion rotating with reel 22. The stationary portion of thebrake means is secured to reel frame 28 wherein are provided hydraulicconnecting means 48 adapted to actuate the brakes.

Referring back to FIGURE 7, pumps 26L and 26R are connected to developpressure in a hydraulic system, generally designated at 48. A staticpressure fluid reservoir 54 is connected by a standpipe 56 to bothhydraulic brake assemblies 23L and 23R in order to maintain a constantminimum static pressure on the brake assembly and thus a slight amountof tension on the pendant 12, and payout means 20. As indicated by thearrows associated with the hydraulic system 48, in addition tore-circulation of hydraulic fluid by pump 26R to and from reservoir 52through lines 50, 55 and 59, fluid is also pressurized in line 51connected to brake assembly 23R. In like manner, pump 26L, in additionto recirculating hydraulic brake fluid to and from reservoir 52, throughlines 50 and 59, also pressurizes line 53 to sensing cylinder 60, whichis interposed between the reservoir 52 and brake assembly 23L.

A normally open shuttle valve 57 is placed at one end of line 51 betweenlines 55 and 56 to permit static pressure between reservoir 54 to beapplied to the right brake 23R through line 51 while at the same timerestricting line 55 on the high pressure side of the right pump 26R.When the right pump 26R is actuated by rotation of the reel 22, thepressure from the pump overcomes the static pressure acting on thepiston of shuttle valve 57, and shifts this piston to allow pumppressure to be applied to the brake through line 51. With pump 26R thusin operation, pressure from static reservoir 54 is cut off to brake 23R,and fluid is slowly metered by metering valve 61R to reservoir 52 atsuch a rate as to maintain a predetermined pressure within the system.

In like manner, a normally open shuttle valve 63 is interposed betweenline 67 and line 56 to permit static pressure from reservoir 54 to reachthe left brake 23L while blocking line 67. When the left pump 26L isactuated, pressure from the pump through line 53 acting on the sensingcylinder piston 66 relays pressure through line 67 to shuttle valve 63whose piston then shifts to block line 56 to reservoir 54, and allowssensing cylinder pressure to react on the brake 23L through line 56. Ameteraraaaea 7 ing valve 61L is disposed in line 59 between lines 53 and55 to provide and maintain any desired operating pressure on this sideof the system.

For a better understanding of the function and construction of thesensing cylinder 60, reference is now made again to FIGURE 8. It will berecognized that when a friction type disk assembly, such as employedwith this embodiment of the invention, becomes heated due to coaction ofone disk against the other, the coefficient of friction of the brakewill correspondingly change, likewise static and high running speedcoeflicients of friction are not the same. Nevertheless, a uniformretarding load is desirable throughout the engagement of the aircraft,and the sensing cylinder, as will be described more fully hereinbelow,acts to proportionately decrease the brake pressure as the coeflicientof friction of the brake disks increases and vice versa.

Hydraulic brake fluid is received from pump 26L at port 62 to exertpressure against the end 64 of piston 66. This pressure is transmittedby piston 66 to port 68 which in turn is connected to line 67, thepressure therein actuating brake 23L. The piston 66 is provided with afollower sheave 70 adapted to make engagement with payout tape 24) andto sense the tension in the payout tape. Thus, as the reel rotates,thereby causing the pump 26L to apply pressure to brake 23L, the tensionin tape 20 increases. The tape tension is sensed by sensing cylinder 60in that a thrust is applied against follower sheave 70 to force thepiston 66 inwardly. As piston 66 is moved inwardly, pressure in line 67is relieved to a degree wherein the tape tension is then proportional tothe pump pressure. If the coeflicient of friction in brakes 23L and 23Ris higher than normal, the tension in the tape, and the consequent forcevector acting on the sensing cylinder follower sheave 70, is increasedforcing the piston 66 inwardly to reduce the brake line 67 pressure,thereby decreasing the amount of braking, and relieving the tension inthe tape 20. If the coeflicient of friction in brakes 23L and 23R islower than normal, the tension in the tape and force on the sensingcylinder follower sheave is decreased, and piston 66 moves outwardly toincrease the pressure in line 67 acting on the brake 23L.

This is a very sensitive mechanism and is responsive to slight changesin coefiicient of friction with the net effect of modulating oraveraging such changes to provide a smooth constant deceleratinginfluence on the landing aircraft. The payout tape 20 is shown in twopositions on the reel 22 to illustrate that the angle of wrap about thesensing follower sheave 70 is less at the start of the payout as shownby the aircraft 10 in FIGURE 10, position 1, than is the angle of wraptoward the end of the payout when the aircraft is at Position 2. It willbe recognized that the resultant component of force acting against thepiston 66 increases as the angle of wrap of tape increases.

When longer runways are available and/ or heavier aircraft landing athigher speeds must be arrested, the embodiment of our invention shown inFIGURE 6 is applicable. Herein we have shown a series of arrestingengines with dual tape reels to increase the energy absorbing capacityof the system and yet maintain a relatively small size unit. The reelsshown in tandem are provided with pairs of spools 72 and 74. The spoolsidentified by the numeral 72 are adapted to permit a payout of tapes 20Ato the left as shown in FIGURE 6, and the spools identified by theirnumeral 74 are adapted to provide a payout of tapes 208 to the right.This arrangement then retains the features of low inertia which permithigh engaging speeds such as are inherent in the single reel embodimentof the invention already described. The tandem arrangement provides forgreatly increased energy absorbing capacity. Each spool is connected toits mating spool by means of an over-running clutch 22C arrangement ofany conventional design well understood in the art, whereby if anunexpected or excessive demand is placed on one side of the system ascompared to the demand on the opposite side, such as developed byoff-center engagement, the high demand side of this system will bepermitted to slip or yield in order to provide the extra payout whichthis side of the system is demanding. This clutch construction issubstantially identical to that employed with the embodiment of theinvention shown in FIGURE 2, and of course may be installed similar tothe arrangement shown in FIGURE 11, wherein tandem spools 72 may belocated on one side of the runway and tandem spools 74 may be located onthe opposite side in lieu of the single spools shown in FIGURE 11.

Reference is now made to FIGURES l2 and 13 wherein is illustrated yet athird embodiment of our invention in which we employ the principles of awater brake for the same purposes as set forth and described heretoforewith respect to the embodiments of FIGURES 2 and 7.

Generally stated, a water brake within the concept of our invention, isa hydro-dynamic device that absorbs power by converting mechanicalenergy into heat in its working liquid medium, this liquid mediumnormally being water. Resistance is created exclusively by fluidfriction and agitation of the water circulated between vaned pockets ofthe rotor and stator elements, with the conversion of mechanical energyinto heat taking place directly within the water itself. The amount ofmechanical energy that can be absorbed in this manner is dependent uponthe quantity and velocity of the water in the working chamber.

Reference is now made more specifically to FIGURE 12 wherein a typicalwater brake 69 is shown partially in section. Water from inlet 71 passesdirectly into supply chambers 73 in each of housing 75 of the stator 77.From the stator supply chamber 73, water enters into each side of theworking chamber 79.

The revolving speed of the water brake 69 under any load condition iscontrolled by the quantity of water in its working chamber 79. As theload varies, a constant revolving speed may be maintained by varying thestatic head 95 in the circulating system (see FIGURE 13) and statorsupply chambers 73, or the volume of water entering the brake inletwhich governs the quantity of water in the working chamber. When therotor 35 is revolved in the direction to create resistance, the water inthe rotor vaned pockets 87 moves to the outer ends of the pockets bycentrifugal force where it is forced across into the vaned pockets 89 ofthe stator 77. As the vaned pockets S9 of the stator 77 are filled, thewater in them is forced back across into the rotor vaned pockets 87 atthe innermost point; and this cycle is repeated as long as the brake isrevolved in a direction to create resistance. The fluid friction andagitation that thereby results develops a resistance against therevolving rotor that converts the mechanical energy into heat in thewater.

It will be readily seen that with any specific quantity of water in theworking chamber, the velocity of the water circulated back and forthbetween the vaned pockets 87 and 89 of the rotor 85 and stator 77respectively will be increased with the increased angular velocity ofthe rotor 85 with resultant increased fluid friction and agitation. Inthis manner, the horsepower capacity of the water brake increasesapproximately in proportion to the cube of its speed. If the speed isdoubled, the horsepower resistance is increased eight times. Thus, therevolving speed limitation of the rotor is mechanical, but thehorsepower capacity of the brake increases with speed in the above ratioto the maximum possible operating speed based on the physical capacityof the brake structure.

For our purposes, however, it is enough to analogize the similaritybetween the water brake embodiment of our invention, and embodiments ofour invention wherein a fluid medium is acted upon in direct proportionto the angular velocity of the reel to apply braking effort against reelrotation. Thus, in the first two embodiments of our invention alreadydiscussed, rotation of the reel drives a hydraulic pump which in turnpressurizes a hydraulic systern designed to apply hydraulic forceagainst a mechanical brake. In the water brake embodiment of ourinvention, the rotor 85 is the hydraulic pump, and the stator 77 is thebrake, such that the faster the reel is rotated, the greater will be thecoaction between the pump 85 and the brake 77 to resist reel rotation.Therefore, it follows that in all embodiments of our invention, ahydraulic pump is an element of the combination, which acts against abrake, whether it be fluid or mechanical, in proportion to the velocityof the reel, the rotation of which provides energy for the hydraulicpump.

Reference is now made to FIGURE 13, wherein is shown a schematicrepresentation of a typical circulating and control system for the waterbrake embodiment 69 of our invention. A valve 91 is provided in thesupply line 93 leading from a static head 95 to the water brake 69.Valve 91 is adapted to control the rate at which water which can enterthe water brake. This control is obtained in a manner quite similar tothe programming means described relative to the brake system shown inFIGURE 2. For instance, a gear box 49 is chain-driven to reel shaft 97and is selected to rotate cam plate 51 one revolution per cycle ofarrestment. Thus cam follower 53 is secured to gate or throttle means invalve 91 for controlling the flow of water therethrough. The valvecapacity is adjusted proportional to the need for maintaining a giventension on the aircraft. When the reel is rotating at a high angularvelocity proportionately less water is required for coaction between thehydraulic pump rotor 85 and the hydraulic brake stator 77. However, asthe angular velocity of the reel decelerates, or higher tension isrequired, valve 91 is proportionately opened to permit an increased rateof flow of water into the water brake 69 sufiicient to maintain thedesired tension on the tapes 20A and 20B. 1

Although programming means are not essential to successful aircraftarrestment by any of the embodiments of our invention, it is a usefulcontrol feature. In addition to providing tension control duringarrestment, it is also very useful in adjusting the system for runoutsof different lengths, as well as for providing means for adjusting forarrestment of different weight aircraft, wherein the runout may be thesame, but the programmed tension requirements may difler. It followstherefore that various combinations of runout and tension controladjustments are possible with our programming means.

We consider of particular significance and importance to the successfuloperation of all embodiments of our invention discussed and disclosedherein the coaction and configuration of the reel and tape. Heretoforethey have been touched upon generally, but specifically the advantagesof our design will now be discussed in greater detail. We consider it tobe particularly important that the tape be of a flat, wide bandconfiguration wherein the width is great compared to the thickness ofthe tape sufficient to permit the tape to spirally wind and unwind uponitself concentrically layer upon layer. This is a distinct departure, tothe best of our knowledge, from all prior art reeling mechanisms,wherein the material being wound on a reel is not amenable to coilbuilding upon itself. For instance, with wound material such as wirecable, it is necessary to traverse the cable back and forth along theaxis of rotation of the reel in order to build layers which aresuificiently stable to provide reliability in winding and unwindingoperations. This method of reel winding is practically universal inapplication and, prior to our invention, was the only method for windinga payout element on a reel.

Now, however, by resorting to our novel configuration of tape, severaladvantages become apparent upon consideration. In the first place, it ispossible with our tape configuration to impart sutficient strength tothe synthetic fiber to enable the withstanding of the high forces oftension to which the fibers must be subjected. Additionally, theconfiguration of the tape lends itself to ease of handling andreliability in winding and unwinding, such that there is practically nopossibility of fouling of the tape on the reel. This becomes readilyapparent in view of the fact that there is no wedging action betweenadjacent turns of the tape such as is inherent in wire cable woundpayout reels. Additionally, kinking, overlapping, binding and most otherdisadvantages of cable wound reeling are eliminated by our tapeconfiguration.

Another and important benefit resides in using fiat wide tape which canbe coiled radially by laminating one layer of tape concentrically uponanother. This benefit is found in a moment arm mechanical advantagewhich operates to increase the eificiency of the system, regardless ofwhether the apparatus is employed in launching or arresting operations.

Reference is now made to FIGURES 14 through 17 which illustrate theweave of the tape which we have adopted for use in our invention. Itwill be observed that the tape 16% comprises a plurality oflongitudinally aligned load bearing strands 170, transversely boundtogether by a strand 172 passing from side to side. In addition to thelongitudinal strands 170 and the transverse strands 172, smallerlongitudinal strands 174 adjacent to longitudinal strands 170 extendlongitudinally (FIGURE 14) and from top to bottom of the tape (FIGURES15 and 17) to lock the top surface of the tape to the bottom surface.Thus, longitudinal strands 170 function as load bearing members in thetape, transverse strands 172 function to hold the tape conformity fromside to side, and longitudinal strands 174 function to maintainconformity in the tape from top to bottom.

FIGURE 18 schematically illustrates the path of weave of the transversetape 172 as it passes from side to side. FIGURES 19 and 20 illustratethe manner in which the tape is woven. It will be seen herein that aplurality of spools of monofilament yarns 176 are mounted on a creel 178and each strand from each spool is fed into a bobbin assembly 180mounted on the warper 182. The finished tape 169 passes over an idlerroll 184 and is wound on reel 185. The technique of weaving the tape,not being the subject of this invention, will not be discussed in anyadditional detail inasmuch as these methods are well known to thoseskilled in the textile arts.

We employ drawn nylon for our tape, but recognize that other syntheticfibers can also be used such as rayon,

' for instance, and we further recognize that with the rapidly advancingtechnology of synthetic fibers still other fibers will eventually bedeveloped which may prove to be of even greater utility than nylon.However, a high tensile strength synthetic fiber is required because ofits resistance to moisture, rot, mildew, and adverse eifects of theouter layer of the tape to the axis of the rotation of the reel is atits greatest at the instant that the pendant is engaged by the aircraft.The result is that the coaction between tape and reel is at its maximummechanical advantage in order to set the system in motion with the leastforce. Additionally this concept of flat tape, wide in relation to itsthickness so as to be capable of being spirally wound on a reel in asingle stack of concentric layers, is inherently capable of beingdesigned to provide a smooth non-pulsating payout. Tape thickness, reeland spool diameter, and torque requirements are of course variableswhich can and must be determined on an individual basis by engineersskilled in the art to meet demands expected to be imposed on aparticular installation. To our knowledge, no other arresting orlaunching system, prior to our concept, has this inherent capability.Thus in a correctlydesigned system, constructed in accordance with ourteaching, as the tape pays out the moment arm progressively decreasessuch that the torque applied to the system by the momentum of theaircraft is proportionately reducing at the same rate as the aircraftdeceleration. However, because the efiective diameter of the reeldecreases as the tape is payed out, the reel angular velocity tends toremain substantially constant. Since brake resistance is proportional toreel velocity, the tape tension acting on the aircraft is maintainedrelatively constant. The combination of reel and tape, therefore can beanalogized to a velocity sensitive gear reduction system, orcontinuously variable transmission, to provide aircraft retarding forceresponsive to changes in aircraft velocity.

Considering now a launching operation, the tape is initially paid out toits full length wherein the minimum moment arm of the reel issubstantially equal to onehalf the radius of the reel drum. However, inthis situation, the forces are reversed and it is the reel which mustpull the aircraft rather than the aircraft which is pulling the reel asin arrestment operation. Thus, it is highly important that initially themoment arm of the reel be small in order to obtain the greatest possibleturning effort in assisting aircraft to overcome its inertia of rest.However, once the aircraft is in motion and is being brought up tospeed, the torque requirements on the reel become progressively reducedat the same time that reel speed must progressively increase. This isautomatically provided by our tape which is winding upon itself anddeveloping a moment arm of ever-increasing radius such that when theleast torque and highest speed is required of the reel the torque hasbeen reduced to its lowest level approximately at the time the aircraftbecomes airborne. Thus, of all of the novel features and advantages ofour developments, we consider the coaction of our novel tape and reel tobe of primary importance to the successful operation of our invention.

It is to be understood that whereas several embodiments of our inventionhave been described hereinabove, these embodiments are by way of exampleonly and are not to be construed in a limiting sense. It is recognizedthat other arrangements and modifications will readily occur to thoseskilled in the art upon reading the specification and the attachedclaims taken in conjunction with the included drawings. These otherarrangements and modifications if based upon the teaching of ourinvention are intended to be covered within the spirit and scope of theappended claims.

We claim:

1. In aircraft arresting gear of the class described including a runwaypendant adapted to be engaged by an aircraft while in motion, theimprovement in rotary friction overrun gear comprising: pendant payoutreel means; pendant payout means connected to opposite sides of saidpendant and to said reel means; fluid operable brake means adapted toretard rotation of said reel means; fluid pump means operable byrotation of said reel means; and fluid means responsive to the operationof said pump means to engage said brake means with said reel means,whereby the back tension on said pendant provided by said reel means isa function of the velocity of said reel means.

2. The device set forth in claim 1 wherein said pendant payout meanscomprises drawn nylon tape woven from longitudinal and transversestrands, said longitudinal strands being conterminous between saidpendant and said reel means.

3. The device set forth in claim 1, wherein said reel means comprises: apair of spools, each spool being adapted to receive pendant payout meansfrom one side of said pendant; and clutch means adapted to couple saidspools one to the other, whereby off-center engagement of said pendantwill enable one spool to payout at a rate greater than the other spool.

4. The device set forth in claim 1, wherein said reel means comprises: aplurality of pairs of spools, said pairs of spools being arranged intandem and each spool of each pair of spools being adapted to receivependant payout means from one side of said pendant, said pendant payoutmeans comprising a plurality of like flat tapes suificiently widerelative to their thicknesses to payout 12 from said tandem reels inover-laying laminated layers.

5. The device set forth in claim 1, wherein said pendant payout meanscomprises tape that is wide and flat relative to its thickness, saidtape being spirally wound upon itself to payout from ever-diminishingspirals, whereby the co-action between said reel means and said tapeprovides a continuously variable transmission to maintain asubstantially constant rate of rotation of said reel.

6. The device set forth in claim 1, wherein said pendant payout meanscomprises flat tape that is sufficiently wide relative to its thicknessto permit said tape to be spirally wound upon itself to payout from saidreel means from ever-diminishing spirals, whereby the moment arm of saidtape measured from its outer periphery to the axis of said reeldecreases as the speed of the aircraft decreases.

7. The device set forth in claim 1, wherein said pendant payout meanscomprises a continuously variable transmission adapted to maintain aconstant tension on said pendant as said aircraft landing speeddiminishes to zero.

8. The device set forth in claim 1, wherein said pendant payout meanscomprises a continuously variable transmission adapted to maintain aconstant tension on said pendant as said aircraft landing speeddiminishes to zero, said transmission including pendant payout tape thatis sufficiently wide relative to its thickness to permit said tape to bespirally wound upon itself so as to pay out from said reel means fromever-diminishing spirals, whereby the acting moment arm of said tapemeasured from the periphery of said spirally wound tape to the axis ofsaid reel means decreases as the speed of the aircraft decreases.

9. In aircraft arresting gear of the class described including runwayarresting pendant means, the improvement in friction overrun gearcomprising: pendant payout reel means; pendant payout means connected toopposite sides of said pendant and to said reel means; fluid operablebrake means adapted to retard the rotation of said reel means; staticpressure means adapted to maintain said brake means in engagement withsaid reel means; fluid pump means operable by rotation of said reelmeans; and fluid means responsive to the operation of said pump means toengage said brake means with said reel means in excess of said staticpressure means, whereby the back tension on said pendant provided bysaid reel means is a function of the velocity of said reel.

10. In aircraft arresting gear of the class described including runwayarresting pendant means, the improvement in friction overrun gearcomprising: pendant payout reel means; pendant payout means connected toopposite ends of said pendant and to said reel means; fluid operablebrake means adapted to retard rotation of said reel means; static fluidpressure means adapted to maintain said brake means in engagement withsaid reel means; fluid pump means operable by rotation of said reelmeans; and fluid means responsive to the operation of said pump means toengage said brake means with said reel means, whereby the back tensionon said pendant provided by said reel is a function of the velocity ofsaid reel.

11. In aircraft arresting gear of the class described including runwayarresting pendant means, the improvement in friction overrun gearcomprising; a pendant payout reel; pendant payout means connected toopposite ends of said pendant and to said reel; fluid operable brakemeans adapted to retard rotation of said reel; fluid pump means operableby rotation of said reel; fluid means responsive to the operation ofsaid pump means to engage said brake means with said reel; a sensingcylinder interposed between said fluid means and said brake means, saidsensing cylinder including a piston positioned to relay pressure in saidfluid means; and a sheave attached to said piston in position to engagesaid pendant payout means, whereby the direction of movement of saidpiston is a .13 function of the tension in said pendant payout means andthe pressure of said fluid means acting on said piston.

12. In aircraft arresting gear of the class described including runwayarresting cable means, the improvement in friction overrun gearcomprising: a pendant payout reel; payout means connected to oppositeends of said pendant and to said reel; a hydraulically operable brakemeans adapted to retard rotation of said reel; hydrostatic means adaptedto hold said brake means in engagement with said reel; hydraulic pumpmeans operable by rotation of said reel; hydraulic means responsive tothe operation of said pump means adapted to hold said brake means inengagement with said reels; a sensing cylinder interposed between saidpump means and said brake means, said sensing cylinder including apiston positioned to relay pressure in said hydraulic means; and asheave attached to said piston in a position to engage said pendantpayout means, whereby the actuation of said piston is also a function ofthe tension in said pendant payout means.

13. In aircraft arresting gear of the class described including runwayarresting pendant means, the improvement in friction overrun gearcomprising: pendant payout reel; pendant payout means connected toopposite ends of said pendant and to said reel; a first fluid operablebrake adapted to retard rotation of said reel; first fluid pump meansoperable by rotation of said reel; fluid means responsive to theoperation of said first pump to engage said first brake with said reel;a second fluid operable brake adapted to retard rotation of said reel;second fluid pump means operable by rotation of said reel, said fluidmeans being responsive to the operation of said second pump to engagesaid second brake with said reel; and hydro-static fluid pressure meansconnected to said first and second brakes adapted to hold said brakes inengagement with said reel until said fluid means responsive to theactuation of said pump means acts to engage said first and secondbrakes, whereby the back tension on said pendant provided by said reelis a direct function of the velocity of said reel and said fluidpressure means.

14. In aircraft arresting gear of the class described including runwayarresting pendant means, the improvement in friction overrun gearcomprising: a pendant payout reel; pendant payout means connected toopposite ends of said pendant and to said reel; a first fluid operablebrake adapted to retard rotation of said reel; first fluid pump meansoperable by rotation of said reel; fluid means responsive to theoperation of said first pump to engage said first brake with said reel;a second fluid operable brake adapted to retard rotation of said reel;second fluid pump means operable by rotation of said reel, said fluidmeans being responsive to the operation of said second pump to engagesaid second brake with said reel; feedback sensing means interposedbetween said second pump and said second brake adapted to relay outputinformation from said second pump to said second brake, said sensingmeans including a cylinder-encased piston, a piston rod, and a sheaveconnected to said piston rod for engagement with said pendant payoutmeans.

15. The device set forth in claim 14, including static fluid pressuremeans adapted to hold said brakes in engagement with said reel.

16. In aircraft arresting gear of the class described including runwayarresting means, the improvement in friction overrun gear comprising: apendant payout reel; nylon tape that is flat and is sufliciently widerelative to its thickness to permit said tape to be spirally wound uponitself, said tape being secured to each end of said pendant and to saidreel; means to wind said tape on said reel to provide payout of saidtape in equal and opposite directions; fluid operable brake meansadapted to provide back tension on said tape as it is being paid out;fluid pump means; fluid means responsive to the operation of said pumpmeans to engage said brake means with said reel; feed-bac sensing meansinterposed between said pump means and said brake means, said sensingmeans including a cylinder-encased piston, a piston rod, and a sheaveconnected to said piston rod for engagement with said tape.

17. The device set forth in claim 16, including a positionalrelationship between said sheave and a fully wound reel wherein theangle of wrap of said tape on said sheave increases as said reel paysout said tape.

18. In aircraft arresting gear of the class described including runwayarresting pendant means, the improvement in friction overrun gearcomprising: flat tape secured to each end of said pendant means; a tapepayout reel; means to secure tape ends remote from said pendant means tosaid reel; means to wind and to payout said tape on said reel; brakemeans adapted to retard rotation of said reel; static means to hold saidbrake means in engagement with said reel; hydraulic pump means operableby said reel; hydraulic means responsive to the operation of said pumpmeans adapted to engage said brake means with said reel; secondhydraulic means responsive to operation of said pump means adapted tohold said brake means in engagement with said reel; said secondhydraulic means including a servo feed-back cylinder interposed betweensaid pump means and said brake means, said cylinder including a pistonpositioned to relay pressure in said hydraulic means; and a sheaveattached to said piston and positioned to engage one of said tapes.

19. In aircraft launching and arresting gear of the class described, theimprovement comprising: a runway pendant engageable by an aircraft; reelmeans; flat, wide band tape means connected to opposite ends of saidpendant and windable on said reel means; brake means adapted to retardrotation of said reel during arresting operations; and reel rotatingdrive means to wind said tape means on said reel in ever-increasingsingle stack concentric layers.

20. In aircraft launching and arresting gear of the class described, theimprovement comprising: a runway pendant engageable by an aircraft; reelmeans; flat, wide band tape means connected to opposite ends of saidpendant and windable on said reel means; fluid operable brake meansadapted to retard rotation of said reel means; pump means operable byrotation of said reel means to energize said brake means duringarresting operations, whereby back tension in said tape means providedby said reel energized pump and brake means is a function of the angularvelocity of said reel means; and reel rotating drive means to wind saidtape on said reel.

21. The apparatus set forth in claim 20, including programming meansadapted to regulate the brake horsepower output of said brake means,whereby the back tension in said tape means is maintained at apredetermined level.

22. The apparatus set forth in claim 20 including a system ofrecirculating fluid connected to said brake means and actuated by saidpump means; a fluid reservoir in said system; a pressure controllingthrottle valve in said system; and means toautomatically adjust saidthrottle valve responsive to rotation of said reel means, whereby thepressure applied to said brake means is regulated.

23. The apparatus set forth in claim 20, including a system ofrecirculating fluid connected tosaid brake means and actuated by saidpump means; a fluid reservoir in said system; a throttle valve in saidsystem on the intake side of said pump means; and means to automaticallyadjust said throttle valve responsive to rotation of said reel meanswhereby to regulate the brake horsepower output of said brake means.

24. The apparatus set forth in claim 20, including a system ofrecirculating fluid connected to said brake means and actuated by saidpump means; a fluid reservoir in said system; a throttle valve in saidsystem on the high pressure side of said pump means; and means toautomatically adjust said throttle valve responsive to ro- 15 tation ofsaid reel means, whereby to regulate the brake horsepower output of saidbrake means.

25. The apparatus set forth in claim 20, including a system ofrecirculating fluid actuated by said pump means; a first fluid reservoirin said system connected across said pump means; a second reservoir insaid system connected directly to said brake means; means to pressurizesaid second reservoir; and shuttle valve means in said system normallyopen between said second reservoir and said brake means, and normallyclosed between said pump means and said brake means; and meansresponsive to energization of said pump to shift said shuttle valve toshut off said second reservoir from said brake means, and to connectsaid pump means to said brake means.

26. The apparatus set forth in claim 20, wherein said reel meanscomprises a pair of tape winding spools mounted on opposite sides of arunway; and said tape means comprises a pair of tapes, each connected toone end of said pendant and to one of said spools; separate pump andbrake means associated with each spool; and separate spool rotatingdrive means to spirally wind said tapes on said spools.

27. In aircraft launching and arresting gear of the class described,including a runway pendant adapted to be engaged by an aircraft, pendantpayout means, and means to apply back tension to said pendant, theimprovement in pendant payout means comprising: a reel; tape that iswide and flat relative to its thickness connected at its ends to theends of said pendant, and at its center to said reel; and means tospirally wind said tape on said reel to build a coil of concentriclayers of tape, whereby during arrestment said tape pays 01f from saidreel in ever-diminishing spirals to provide a continuously variabletransmission adapted to maintain a substantially constant rate ofrotation of said reel.

28. In aircraft launching and arresting gear of the class describedincluding a runway pendant adapted to be engaged by an aircraft, pendantpayout means, and means to apply back tension to said pendant, theimprovement in pendant payout means comprising: a pair of concentricallyrotatable spools; a pair of tapes that are each wide and flat relativeto thickness, each tape being connected at one end to an end of saidpendant and at its opposite end to one of said spools; and means tospirally wind said tapes on said spools to build a pair of coils ofconcentric layers of tape, whereby during arrestment said tapes pay offfrom said spools in oppo- 16 site directions and in ever-diminishingspirals to provide a continuously variable transmission adapted tomaintain a substantially constant rate of rotation of said spools.

29. In aircraft launching and arresting gear of the class describedincluding a runway pendant adapted to be engaged by an aircraft, theimprovement in pendant payout means comprising: a reel positioned oneach side of a runway; a pair of tapes that are each wide and flatrelative to thickness, each tape being connected at one end to an end ofsaid pendant, and at its opposite end to one of said reels; and means tospirally wind said tapes on said reels to build coils of concentriclayers of tape; whereby during arrestment said tapes payoff from theirrespective reels on opposite sides of said runway in everdecreasingspirals to provide continuously variable transmissions adapted tomaintain substantially constant velocities of rotation of said reels.

30. In aircraft launching and arresting gear of the class described,including a runway pendant adapted to be engaged by an aircraft, pendantpayout means, and means to apply back tension to said pendant, theimprovement in pendant payout means comprising: a plurality of reelsarranged in tandem, a like plurality of tapes each of which is wide andflat relative to its thickness, each tape being connected at one end toa corresponding reel, and at its opposite end to one end of saidpendant; means to spirally wind each tape on its reel to concentricallybuild a coil layer upon layer; and means to simultaneously payoff saidtapes in aligned overlaying laminated relationship.

31. The apparatus set forth in claim 30, wherein a plurality of tandemgrouped reels are positioned on opposite sides of a runway, the tapes ofeach tandem grouping being connected in laminated relationship to oneend of said pendant.

References Cited in the file of this patent UNITED STATES PATENTS2,712,912 Hattan July 12, 1955 2,866,483 Watts et al. Dec. 30, 19582,896,396 Kenyon July 28, 1959 2,971,727 Haber Feb. 14, 1961 2,987,278Hoffman et al. June 6, 1961 OTHER REFERENCES Aviation Week, September23, 1957, pages 86, 87, 89, 91, 93, 95, 97 and 99.

20. IN AIRCRAFT LAUNCHING AND ARRESTING GEAR OF THE CLASS DESCRIBED, THEIMPROVEMENT COMPRISING: A RUNWAY PENDANT ENGAGEABLE BY AN AIRCRAFT; REELMEANS; FLAT, WIDE BAND TAPE MEANS CONNECTED TO OPPOSITE ENDS OF SAIDPENDANT AND WINDABLE ON SAID REEL MEANS; FLUID OPERABLE BRAKE MEANSADAPTED TO RETARD ROTATION OF SAID REEL MEANS; PUMP MEANS OPERABLE BYROTATION OF SAID REEL MEANS TO ENERGIZE SAID BRAKE MEANS DURINGARRESTING OPERATIONS, WHEREBY BACK TENSION IN SAID TAPE MEANS PROVIDEDBY SAID REEL ENERGIZED PUMP AND BRAKE MEANS IS A FUNCTION OF THE ANGULARVELOCITY OF SAID REEL MEANS; AND REEL ROTATING DRIVE MEANS TO WIND SAIDTAPE ON SAID REEL.